My new build lawn has very few worms - and I could do with some to improve
drainage, and the general condition of the under-soil. Can worms be bougth
mail order and simple scattered on the surface ? Or have missed the boat
now that the lawn is down and doing well ?


The worms should colonise your lawn on their own.
If this is not the case then bought in worms will not colonise it either.



ah, fair enough. Just wait and see then. I have spotted the odd one -
hopefully is an indication of a growing underground city !